Over a week after the magnitude 9 earthquake and the massive tsunamis it triggered, information continues to coalesce on the health risks from the Fukushima Daiichi nuclear power station explosion. Here’s a roundup of what various people are saying about radiation and other threats.

First, here is the latest info from the Japanese government on radioactivity measurements. And here’s today’s update on the location of the radiation plumes.

That all adds up to about 2.4 units, known as millisieverts (mSv), a year – though it varies from 1 to 10 mSv depending on where you live. The average American absorbs 6.2 mSv a year. US guidelines recommend evacuation with 10 to 50 mSv.

In Tokyo, 150 miles from the nuclear plant, readings rose about 10 times above the norm. That’s 0.809 microsieverts (not milli) per hour – or about 10 times less than a chest X-ray.

A Japanese broadcast reported0.17 mSv per hour 30 km northwest of the reactor. There're also reports of 0.012 mSv/hr in Fukushima City, 60 km away from the plant.

Potassium iodide, which there are ample supplies of, prevents radiation poisoning of the thyroid gland. The drug blocks the uptake of radioactive iodine by filling the gland with a safer form of iodine.

Outside the immediate vicinity of the nuclear site, the primary danger is airborne radioactive material released into an atmospheric plume. That material can pose additional hazards if inhaled, swallowed or absorbed through the skin to emit radiation from inside the body.

Janet Fang has written for Nature, Discover and the Point Reyes Light. She is currently a lab technician at Lamont-Doherty Earth Observatory. She holds degrees from the University of California, Berkeley and Columbia University. She is based in New York.
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